#! /usr/bin/env python

# Copyright (c) 2017, Thierry Carrez
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import calendar
import copy
import datetime
from itertools import chain
import json
import os
import random


class PTGDataBase():

    BASE = {'tracks': [], 'slots': {}, 'now': {}, 'next': {}, 'colors': {},
            'location': {}, 'scheduled': {}, 'additional': {}}

    def __init__(self, config):
        self.filename = config['db_filename']
        self.slots = config['slots']
        self.scheduled = config['scheduled']
        self.extrarooms = config['extrarooms']

        if os.path.isfile(self.filename):
            with open(self.filename, 'r') as fp:
                self.data = json.load(fp)
        else:
            self.data = copy.deepcopy(self.BASE)

        old_data = copy.deepcopy(self.data['additional'])
        self.load_data_from_config()
        self.merge_additional(old_data)
        self.save()

    def load_data_from_config(self):
        # Copy slots definition and scheduled rooms from configuration
        self.data['slots'] = self.slots
        self.data['scheduled'] = self.scheduled

        # Create additional rooms dictionary from extrarooms definition
        for room in self.extrarooms.keys():
            self.data['additional'][room] = {}
            for slot in self.extrarooms[room]:
                self.data['additional'][room][slot] = ''

        # Add tracks mentioned in configuration that are not in track list
        for room, bookings in self.scheduled.items():
            for time, track in bookings.items():
                if track not in self.data['tracks']:
                    self.data['tracks'].append(track)
                    self.data['colors'][track] = random.choice([
                        '#596468',
                        '#9ea8ad',
                        '#b57506',
                        '#f8ac29',
                        '#5b731a',
                        '#9dc62d',
                        '#156489',
                        '#27a3dd',
                        '#2a6d3c',
                        '#3fa45b',
                        '#930a0a',
                        '#dc0d0e',
                    ])

    def merge_additional(self, old_data):
        # Populate 'additional' with saved data where appropriate
        for room in self.data['additional'].keys():
            for slot in self.data['additional'][room].keys():
                try:
                    self.data['additional'][room][slot] = old_data[room][slot]
                except KeyError:
                    pass

    def add_now(self, track, session):
        self.data['now'][track] = session
        # Update location if none manually provided yet
        room = self.get_track_room(track)
        if room and track not in self.data['location']:
            self.add_location(track, room)
        if track in self.data['next']:
            del self.data['next'][track]
        self.save()

    def add_color(self, track, color):
        self.data['colors'][track] = color
        self.save()

    def get_track_room(self, track):
        # This simplified version returns the first room the track is
        # scheduled in for the day. If the event does not run on this
        # day, pick the first day.
        today = calendar.day_name[datetime.date.today().weekday()]
        if today not in self.data['slots']:
            today = next(iter(self.data['slots']))
        all_schedule = chain(self.data['scheduled'].items(),
                             self.data['additional'].items())
        for room, bookings in all_schedule:
            for btime, btrack in bookings.items():
                for slot in self.data['slots'].get(today, []):
                    if btrack == track and btime == slot['name']:
                        return room
        return None

    def add_location(self, track, location):
        self.data['location'][track] = location
        self.save()

    def add_next(self, track, session):
        if track not in self.data['next']:
            self.data['next'][track] = []
        self.data['next'][track].append(session)
        self.save()

    def is_track_valid(self, track):
        return track in self.data['tracks']

    def list_tracks(self):
        return sorted(self.data['tracks'])

    def add_tracks(self, tracks):
        for track in tracks:
            if track not in self.data['tracks']:
                self.data['tracks'].append(track)
        self.save()

    def del_tracks(self, tracks):
        for track in tracks:
            if track in self.data['tracks']:
                self.data['tracks'].remove(track)
        self.save()

    def clean_tracks(self, tracks):
        for track in tracks:
            if track in self.data['now']:
                del self.data['now'][track]
            if track in self.data['next']:
                del self.data['next'][track]
        self.save()

    def is_slot_valid_and_empty(self, room, timeslot):
        try:
            return not self.data['additional'][room][timeslot]
        except KeyError:
            return False

    def book(self, track, room, timeslot):
        self.data['additional'][room][timeslot] = track
        self.save()

    def new_day_cleanup(self):
        self.data['now'] = {}
        self.data['next'] = {}
        self.data['location'] = {}
        self.save()

    def reload(self):
        self.data = copy.deepcopy(self.BASE)
        self.load_data_from_config()
        self.save()

    def save(self):
        timestamp = datetime.datetime.now()
        self.data['timestamp'] = '{:%Y-%m-%d %H:%M:%S}'.format(timestamp)
        self.data['tracks'] = sorted(self.data['tracks'])
        with open(self.filename, 'w') as fp:
            json.dump(self.data, fp)